#include <iostream>
#include <algorithm>
#include <string>
using namespace std;
int main() {
int m,n;
long long X[100][100];
string ans;
cin>>n>>m;
for (int i=n-1; i>=0; i--){
for (int j=0; j<m; j++)cin>>X[i][j];
}
for(int i=1;i<n;i++)X[i][0]=X[i][0]+X[i-1][0];
for(int j=1;j<m;j++)X[0][j]=X[0][j]+X[0][j-1];
for (int i=1; i<n; i++){
for (int j=1; j<m; j++) X[i][j]=X[i][j]+max(X[i - 1][j], X[i][j - 1]);
}
int k=n-1, t=m-1;
while (k>0 || t>0){
if (k>0 && t>0){
if (X[k-1][t]>X[k][t-1]){
ans+="F";
k--;
}
else{
ans+="R";
t--;
}
}
else if (k==0){
ans+="R";
t--;
}
else if (t==0){
ans+="F";
k--;
}
}
reverse(ans.begin(),ans.end());
cout<<ans;
return 0;
}
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